Insurgents Have Amassed Cash Trove From Middle East Donors

PARIS—France called for coordinated international action to cut off the Islamic State's access to financial resources amid fears that the Sunni insurgency has become the world's richest jihadist movement.

French Foreign Minister Laurent Fabius said the extremist group, already a formidable military force, has enhanced its power by amassing huge piles of cash, thanks in part to individual donors from the Middle East.